Portable storage case

ABSTRACT

A portable suitcase-type storage case has structural features that enable to stack the case regardless of the surface shape of the bottom and lid casings, without diminishing its pleasing visual appearance of the storage case. A convex-shaped stacking section is provided integrally with the bottom casing at specific locations on a surface of the bottom casing, and a concave-shaped stacking section is provided integrally on a surface of the lid casing at corresponding locations so as to engage with respective convex-shaped stacking sections, in such a way that a radius of curvature of the concave-shaped stacking section is greater than a radius of curvature of the convex-shaped stacking section, and that a center portion of the concave-shaped stacking section is displaced towards outer periphery of the storage case relative to a center portion of the convex-shaped stacking section.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a portable storage case such as suitcases or containers for storing and transporting of musical instrument, and relates in particular to a portable storage case, made of ABS resin and the like, having members which enable to stack the portable storage case.

[0003] 2. Description of the Related Art

[0004]FIG. 5 shows a common suitcase, which is formed into a container comprised by a bottom casing 1 having a frame 10 and a lid casing 2 having a frame 20 hinged at a given peripheral edge so as to form a shell that can be opened or closed freely. A handle 4 of a suitable shape and locking members 5 are provided on the frames opposite to the hinged joint 3 so as to enable to transport the case by hand.

[0005] Such portable storage cases are often made of a material such as ABS resin because of the ease of forming during manufacturing, adaptability to a variety of product designs as well as excellent impact resistance of the product.

[0006] On the outer side of the hinged joint 3, some of these cases are provided with leg sections 6 to enable the case to be stood on its end, or some large sized models are available with casters to enable their pulling.

[0007] Also, such portable storage cases include not only suitcases for travelling but also cases for storage and transport of musical instruments such as electronic keyboard instruments or teaching recorder devices.

[0008] Some of these portable storage cases are designed for ease of stacking the cases of the same type for stable transport of flat piled cases.

[0009] Conventional stacking designs include an approach of bonding a soft material of a suitable thickness, such as soft rubber or a flexible resin material, on the four corners of the bottom casing to prevent slipping as well as to prevent damage caused by mutual rubbing of the shell surfaces.

[0010] Storage cases having such stacking provisions enable to stack the cases for efficient utilization of transporting space, for example when transporting a number of cases containing musical instruments for an orchestral group in a vehicle, as well as to prevent sliding of the stacked assembly. Such provisions are also effective for storage and display of inventory goods in retail stores.

[0011] However, such a conventional design for stacking of storage cases presents a number of problems. First, manufacturing process becomes more complex because of an increase in the number of parts and steps required for installing the corner pads, and consequent increase in the cost. Also, such protruding pads spoil the external appearance of the storage case and are therefore not really satisfactory from the viewpoint of users, particularly for products such as suitcases where styling is an important consideration.

[0012] Additionally, although the conventional stacking design had been somewhat effective in situations involving flat surfaces of the bottom and lid casings, lately there has been a shift towards rounded external shape of storage cases because of the introduction of ABS resins and improvements in manufacturing technology. It has therefore become increasingly difficult to achieve stability of vertical arrangement of storage cases based on the conventional stacking design, thus making the stacked assembly vulnerable to collapsing.

SUMMARY OF THE INVENTION

[0013] The present invention is provided in view of the background situation described above, and an object of the present invention is to provide a suitcase-type portable storage case that facilitates stacking by providing spherical shaped engaging bumps and corresponding dimples on both surfaces of the bottom casing and the lid casing, so that not only stacking members can be provided on the portable storage cases without diminishing their design appeal but also stability of the stacked assembly can be assured regardless of the surface shape of the bottom and lid casings.

[0014] To achieve the object, the present invention provides a portable storage case of a suitcase type comprised by a framed bottom casing hinged to a framed lid casing so as to form a shell casing that can be freely opened or closed at a hinged section, and having handle members and locking members provided on frames opposite to the hinged section, wherein a convex-shaped stacking section is provided integrally at a plurality of locations on a surface of the bottom casing, and a concave-shaped stacking section is provided integrally at corresponding locations on a surface of the lid casing so as to engage with respective convex-shaped stacking sections, in such a way that the convex-shaped stacking section and the concave-shaped stacking section are spherically shaped for mutual engaging, such that a radius of curvature of the concave-shaped stacking section is greater than a radius of curvature of the convex-shaped stacking section, and the center of the concave-shaped stacking section is displaced towards outer periphery of the storage case relative to the center of the convex-shaped stacking section.

[0015] Because of the structures of the storage case described above, members which enable to stack the cases can be provided without diminishing the design appeal, and stable stacking is achieved regardless of the surface shapes of the bottom casing and lid casing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIGS. 1A, 1B are, respectively, a perspective view from the bottom casing side and a perspective view from the lid casing side of a suitcase according to an embodiment of the present invention.

[0017]FIG. 2 is a side view of a suitecase according to an embodiment of the present invention.

[0018]FIG. 3 is a diagram to show a method of stacking of suitcases according to an embodiment of the present invention.

[0019]FIG. 4 is a diagram to show the details of an example of engagement of a convex-shaped stacking section and a concave-shaped stacking section for piling portable storage cases according to an embodiment of the present invention.

[0020]FIGS. 5A, 5B are diagrams to show a conventional suitcase in two orientations.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In the following, an embodiment of the present invention will be explained with reference to FIGS. 1 to 4.

[0022]FIGS. 1 and 2 show an example of a suitcase according to an embodiment of the present invention. The suitcase includes a bottom casing 1 and a lid casing 2 having respective frame members 10, 20, which are joined at a hinged section 3 at a given periphery so as to form a freely openable shell structure. A handle member 4 and locking members 5 are provided on frames opposite to the hinged section 3 as in the conventional product, and on the outer side of the hinged section 3, legs 6 are provided suitably so as to enable the suitcase to stand on the end.

[0023] The bottom and lid casings 1, 2 are fabricated of ABS resin and the like, and the hinged section 3 is produced by forming the bottom and lid casings 1, 2 separately and joining the two pieces by appropriate butterfly hinging members, or by thinning the coupling sections of the bottom and lid casings 1, 2 to form an integrated hinging structure.

[0024] And, a plurality of convex-shaped stacking sections 11 are provided on the surface of the bottom casing 1, and a plurality of concave-shaped stacking sections 21 are provided on the surface of the lid casing 2 in such a way that the stacking sections are shaped and positioned to be mutually engaging.

[0025] These convex-shaped stacking sections 11 and concave-shaped stacking sections 21 are shaped spherical, and are formed integrally with the respective bottom casing 1 and the lid casing 2 during their vacuum forming process, for example.

[0026] In the diagrams, the stacking sections 11, 21 are shown to be provided in the corners of the bottom casing 1 and the lid casing 2, but their positioning is not limited to such an arrangement, and is determined in terms of the overall considerations of design and manufacturing cost.

[0027] Accordingly, when the suitcases are to be stacked flat as shown in FIG. 3, the convex-shaped stacking sections 11 of one suitcase engages with the concave-shaped stacking section 21 of another suitcase, thereby enabling to stack several such suitcases.

[0028] Because both stacking sections are round surfaced, suitcases can be stacked by simply sliding one case against another to couple the stacking sections to provide stable stacking, without the need for fine positioning and without causing scratches on the surfaces. The overall curved appearance of the suitcase is visually pleasing and does not diminish its design appeal.

[0029] Further, as shown in FIG. 4, it is preferable that the radius of curvature of the concave-shaped stacking section 21 is set to be large relative to that of the convex-shaped stacking section 11. By so doing, mutual engaging is carried out smoothly so that the stacking task is facilitated even more, and vibration resistance of the stacked assembly is made superior.

[0030] Further, by displacing the center of the concave-shaped stacking section 21 towards the outside of the center of the convex-shaped stacking section 11, the stacked assembly can be made even more stable.

[0031] That is, when the center portion O₂ of the concave-shaped stacking section 21 is displaced towards the outside of the center portion O₁ (apex) of the convex-shaped stacking section 11 by a suitable distance W, the apex O₁ of the convex-shaped stacking section 11 constantly tries to slide towards the center portion O₂ of the concave-shaped stacking section 21 along the curved surface of the concave-shaped stacking section 21, thereby maintaining a stable stacked assembly.

[0032] It should be noted that although the present invention was exemplified by a portable suitcase, it is obvious that the present portable storage case can be used for other purposes such as for transporting musical instruments.

[0033] As explained above, the present invention provides the features summarized as follows: (1) a convex-shaped stacking section is provided integrally with the bottom casing at a plurality of locations on a surface of the bottom casing, and a concave-shaped stacking section is provided integrally on a surface of the lid casing at corresponding locations; (2) a radius of curvature of the concave-shaped stacking section is greater relative to a radius of curvature of the convex-shaped stacking section; (3) the center of the concave-shaped stacking section is displaced towards an outer periphery of the storage case relative to the center of the convex-shaped stacking section; (4) the convex-shaped stacking section and the concave-shaped stacking section can be formed integrally by vacuum forming, and (5) these features can be incorporated without increasing the number of parts during the process of making the shell surfaces to keep the cost low. Additionally, the stacking members are provided without detracting from the design appeal of the product so that the features can be incorporated into suitcases and other portable cases that demand rounded appealing designs.

[0034] When the cases are to be stacked, because the convex-shaped stacking section and the concave-shaped stacking section have a spherical surface, the suitcase can be slid on the surface of the lid casing smoothly to produce a stacked assembly, without the need for careful positioning and without causing scratches on the shell surface, to result in a stable and vibration resistant assembly that does not collapse easily. 

What is claimed is:
 1. A portable storage case of a suitcase type having a framed bottom casing hinged to a framed lid casing so as to form a shell casing that can be freely opened or closed at a hinged section, and having handle members and locking members provided on frames opposite to the hinged section, wherein a convex-shaped stacking section is provided integrally at a plurality of locations on a surface of the bottom casing, and a concave-shaped stacking section is provided integrally at corresponding locations on a surface of the lid casing so as to engage with respective convex-shaped stacking sections.
 2. A portable storage case according to claim 1 , wherein the convex-shaped stacking section and the concave-shaped stacking section are spherically shaped for mutual engaging, such that a radius of curvature of the concave-shaped stacking section is greater than a radius of curvature of the convex-shaped stacking section.
 3. A portable storage case according to claim 1 , wherein the center portion of the concave-shaped stacking section is displaced towards outer periphery of the storage case relative to the center portion of the convex-shaped stacking section. 